This invention relates to methods, compositions and kits for detecting the presence and/or amounts of amphetamine and/or methamphetamine in samples suspected of containing the same. In particular, the invention relates to bivalent hapten conjugates comprising an amphetamine moiety and a methamphetamine moiety. The conjugate may be employed in assays for amphetamine and/or methamphetamine.
The clinical diagnostic field has seen a broad expansion in recent years, both as to the variety of materials of interest that may be readily and accurately determined, as well as the methods for the determination. Over the last decade, testing for drugs of abuse has become commonplace. This testing is not only for the monitoring of criminal offenders and drug addicts, but employers also use it for the screening of workers. In recent years immunoassays based on the reaction of an antibody with an antigen have been extensively investigated for this purpose.
Typically, immunoassays employ an antibody whose structure recognizes an analyte in a specific manner. The immunoassay is conducted with a signal producing system that produces a detectible change in signal upon binding of the analyte to the antibody. Accordingly, when testing for an analyte in a sample, a detectible change in signal from that produced with a negative sample of a calibrator is taken as a positive result for the presence of that analyte in the sample.
Amphetamine and methamphetamine stimulate the central nervous system and have been used medicinally to treat hypotension, narcolepsy and obesity. D-Methamphetamine is used as desoxyn and its 1-methamphetamine is used in certain non-prescription inhalers as a decongestant. Because of their stimulating effects, the drugs and derivatives have been abused. As a result, assays for the detection of amphetamine and/or methamphetamine in samples are of interest.
A number of assays are available for the screening of urine samples for amphetamine and methamphetamine as drugs of abuse. The present assays have the problem of false positives associated with the presence of many amphetamine-related drugs such as phenmetrazine, phentermine and phenylpropanolamine.
There is, therefore, a need for assays for the detection of amphetamine and/or methamphetamine where the number of false positive results are reduced. The assay should have improved sensitivity and specificity, while maintaining or improving on the speed of the assay.